Many of the waste dump sites located throughout the U.S. and indeed, throughout the world, contain hazardous waste including toxic substances. Over time, such hazardous waste can enter the ground, for example with rainwater, and can come in contact with ground water beneath the dump site. Where this occurs, the ground water becomes contaminated.
Such ground water contamination renders the ground water beneath the dump site unusable. Normally, the ground water slowly flows beneath the dump site and thereby carries the contaminants which infiltrated at the dump site with it. Thus, a single dump can contaminate the ground water over large geographical areas far beyond the dump site. This renders the contaminated ground water unusable for most purposes or requires the installation of costly ground water treatment facilities where the hazardous contaminants are removed before the water can be used. As the flow spreads, increasingly large volumes of ground water become contaminated, thereby requiring increasingly large treatment facilities which are expensive to install and to operate.
Thus, efforts are being made to prevent hazardous waste from contaminating ground water flows by containing the contaminants at the dump site and preventing their escape therefrom. The U.S. Environmental Protection Agency (EPA) provides the following guidance for preventing the contamination of ground water flows in the "Remedial Action at Waste Disposal Sites" section of the EPA Handbook which, in relevant parts provides: